Can You Take Claritin And Zyrtec Together?

In our latest question and answer, the pharmacist discusses if it is safe to take Claritin (loratadine) and Zyrtec (cetirizine) together.

Question

Can I take Zyrtec and Claritin together?

Asked by Roberta On Jun 14, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Jun 14, 2018

Woman SneezingZyrtec (cetirizine) and Claritin (loratadine) are both second-generation antihistamines approved for the treatment of seasonal allergic rhinitis and chronic urticaria (a type of skin rash). They should not be taken together. Not only will combined use increase the risk of side effects such as constipation and sedation, there likely won't be any additional benefit when it comes to allergy symptom reduction.


Zyrtec and Claritin work the same way, by blocking the binding of histamine to H1 (histamine-1) receptors. By blocking the binding of histamine, it prevents allergic symptoms from occurring.


Both Zyrtec and Claritin bind fairly strongly to their respective receptors and taking both at the same generally does not result in increased receptor binding (as either Claritin or Zyrtec will be bound). Therefore, taking both is not therapeutically beneficial. You will most likely only have additive adverse reactions, which include:

  • Sedation
  • Constipation
  • Dry eyes
  • Dry mouth
  • Cardiac problems (uncommon)


Both Zyrtec and Claritin may be taken with or without food and may be taken in the morning or in the evening. Each dose lasts around 24 hours.

About the Pharmacist

Dr. Adam DeRue Pharm.D

Dr. Adam DeRue is a Doctor Of Pharmacy and registered pharmacist.

About Claritin (Loratadine)

Claritin (loratadine) is an non-sedating, "second-generation" antihistamine (H1-blocker). Unlike "first-generation" antihistamines, Claritin doesn't penetrate the central nervous system in high concentrations an therefore, does not cause significant sedation. Claritin was first approved by the FDA in April 1993 as a prescription medication and was approved for over the counter sale in December 2002. Claritin may be taken with or without food, with the onset of action occurring within 1 to 3 hours. Peak effects are generally seen in 8 to 12 hours. Claritin has a long duration of action and is therefore dosed once daily.

About Zyrtec (Cetirizine)

Zyrtec (cetirizine) is a "second-generation" antihistamine, indicated for the treatment and prevention of perennial allergies, seasonal allergies and hives. At indicated doses (5mg and 10mg), it generally has a higher incidence of sedation than other second-generation antihistamines, such as Allegra (fexofenadine) and Claritin (loratadine). Nevertheless, it still causes less sedation than older, first-generation antihistamines such as Benadryl. Zyrtec is taken once daily, with an onset of action around one hour.

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